Rio Wastewater Treatment Facility
Rio, WI · Columbia County · Publicly Owned Treatment Works
- Average flow
- 0.34 MGD
- Design flow
- 0.12 MGD
- NPDES permit
- WI0020117
- Expired
- Permit expires
- September 2023
- Population served
- 1,100
- CWNS 2022
Rio Wastewater Treatment Facility is a publicly owned wastewater treatment works in Rio, Columbia County, Wisconsin treating an average of 0.34 million gallons per day against a permitted design capacity of 0.12 MGD, serving about 1,100 residents. Treatment on site includes aerated lagoons, uncovered lagoons. It discharges under NPDES permit WI0020117 (expired), which expires in September 2023, with 2 recorded violations in the last three years.
Treatment technology
Treatment structures identified at this facility. Exact unit counts are available in Klarifi.
Compliance snapshot (last 3 years)
- Total violations
- 2
- Effluent violations
- 2
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
Decision-makers at Rio Wastewater Treatment Facility.
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Nearby wastewater treatment plants in Wisconsin
Cambria · 9 mi away
0.08 MGD
Portage · 11 mi away
1.52 MGD
Friesland · 13 mi away
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Randolph · 13 mi away
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Columbus · 15 mi away
1.03 MGD
Kingston · 17 mi away
0.01 MGD
Lodi · 17 mi away
0.27 MGD
Marshall · 22 mi away
0.37 MGD
Rio Wastewater Treatment Facility: frequently asked questions
Sources and methodology
Flow, permit and violation figures come from the EPA's ICIS-NPDES discharge monitoring records. Population served comes from the Clean Watersheds Needs Survey 2022. Treatment structures are identified by Klarifi's review of aerial imagery, and capital improvement projects are extracted from published municipal budget documents. Violations are counted over the last three years of monitoring reports.
Data refreshed September 11, 2026; facility record last updated November 20, 2025.